Research And Implementation Of The Baseband Algorithm Of Beidou Software Receiver

Beidou system is a global positioning and navigation system that is self-developed by our country. Its goal is to build a global satellite navigation system which provides navigation and other services. In recent years, the Beidou satellite navigation and positioning system has been widely used in various fields. The research on Beidou has gradually formed a new subject. At present, most of the Beidou receiver is a hardware receiver which has the shortcoming of high cost and low flexibility. The software receiver that has the advantages of low cost and high flexibility should be studied.The focus of this thesis is to design and optimize the performance of the software receiver which points at each module of baseband signal processing. In the software implementation, the overall design of the software receiver is carried out, and the acquisition, tracking and positioning of the signal are realized On the PC platform. In the performance optimization software receiver, using the method of reducing the length of the compressed data to reduce the number of the fast Fourier transform. And the method to reduce the computation quantity of the acquisition is used to initialize the fast Fourier transform, so that the search time of a frequency point is less than 1ms,Finally, the whole process of acquisition is reduced by 26 ms. Then the features of tracking channel are real-time requirements and low accuracy of the data. In the premise of ensuring the navigation data symbols, the correlation value of the tracking process is calculated by the method of checking table. And we reduce the amount of computation by gradually reducing the accuracy of the table. In the end, we have the ability to achieve the real-time tracking of satellite signal on the personal computer.Finally, the acquisition process of the software receiver, tracking process and positioning results are analyzed, including the number of satellites, acquisition time, tracking loop performance indicators, the time of tracking process, and positioning accuracy. After verification, it can capture 10 Beidou satellites and can track the satellite signal in real time.And the positioning accuracy is 5 meters.